freightliner Custom Classic MT45 2022, Maintenance Manual

Page: 102 / 138

2. Inspect the slack adjuster for physical damage,
paying attention to the link, boot, and clevis. If
any components are damaged, repair or replace
them as necessary.
3. Measure the brake actuator pushrod stroke while
making an 80 to 90 psi (552 to 621 kPa) brake
application. Actuator pushrod strokes should not
exceed the values shown in
Table 4 and
Table 5 . To achieve the correct pressure for this
test, build the system pressure up to a 100 psi
(690 kPa). Shut down the engine. Fan the
brakes to attain a 90 to 95 psi (621 to 655 kPa)
reading. Make and hold a full brake application
while the strokes are checked.
Actuator Stroke–Standard Stroke
Brake Actuator Size
Recommended Maximum
Operating Stroke (Inches)
30 2
24 1-3/4
20 1-3/4
16 1-3/4
12 1-3/8
Table 4, Actuator Stroke–Standard Stroke
Actuator Stroke–Long Stroke
Brake Actuator Size
Recommended Maximum
Operating Stroke (Inches)
30 Long Stroke 2-1/2
24 Long 2
24 Long Stroke 2-1/2
20 Long 2
16 Long 2
Table 5, Actuator Stroke–Long Stroke
42–10 Bendix Automatic Drain
Valve Operating and
Leakage Tests
Operating Test
Perform the following test after repairing or replacing
the DV-2 valve, to ensure that the valve is function-
ing properly.
With the system charged, apply the brakes several
times. Each time the brakes are applied, an exhaust
of air should occur from the exhaust port of the drain
valve. If no air comes out, push the wire stem lo-
cated inside the exhaust port. If no air comes out
after pushing the wire stem, there may be a plugged
filter in the adapter which should be replaced.
If the drain valve does not function properly, repair or
replace it. See
Section 42.12 of the Walk-In Van
Chassis Workshop Manual .
Leakage Test
Perform the following test after repairing or replacing
the DV-2 valve, to ensure that the valve is function-
ing properly.
With the system charged and pressure stabilized in
the system, there should be no leaks at the drain
valve exhaust port. A constant slight exhaust of air at
the drain valve exhaust port could be caused by ex-
cessive leakage in the air brake system.
If the drain valve is leaking excessively, repair or re-
place it. See
Section 42.12 of the Walk-In Van
Chassis Workshop Manual .
Brakes
42
Walk-In Van Chassis Maintenance Manual, October 2019
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